diff --git a/Appendix-D:-References.md b/Appendix-D:-References.md
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@@ -30,5 +30,7 @@ If you would like to submit a resource link to be added to this list, please pos
 * CVEs (Common Vulnerabilities and Exposures)
    * [mitre.org](https://cve.mitre.org/cgi-bin/cvekey.cgi?keyword=firefox) - **h**ttps://cve.mitre.org/cgi-bin/cvekey.cgi?keyword=firefox
    * [cvddetails.com](https://www.cvedetails.com/vulnerability-list/vendor_id-452/product_id-3264/Mozilla-Firefox.html) - **h**ttps://www.cvedetails.com/vulnerability-list/vendor_id-452/product_id-3264/Mozilla-Firefox.html
+* [Firefox Site Compatibility](https://www.fxsitecompat.com/en-CA/) - **h**ttps://www.fxsitecompat.com/en-CA/
+   * Community-driven Web developer engagement initiative focused on the backward compatibility and regressions in Firefox
 * [Portable Firefox](http://portableapps.com/apps/internet/firefox_portable) - **h**ttp://portableapps.com/apps/internet/firefox_portable
   * [Stable/ESR Releases](http://sourceforge.net/projects/portableapps/files/Mozilla%20Firefox%2C%20Portable%20Ed./) - **h**ttp://sourceforge.net/projects/portableapps/files/Mozilla%20Firefox%2C%20Portable%20Ed./